6i8 



NA TURE 



[November 4, 1922 



glaciated region would cause a constant succession 

 of cyclones accompanied by a high rainfall over the 

 Mediterranean and Western Asia. This would support 

 the view that the desert belt of the Sahara was then 

 more to the south, thus accounting for the vast 

 number of palaeolithic implements, accompanied by 

 ostrich shells, found in that area. It would also 

 strengthen the probability that man drifted north 

 as the climate improved after the Wurm period, 

 and confirm the suggestion of the archaeological 

 evidence that after the Aurignacian period there is 

 no break. 



A series of recent investigations on the south 

 coast in Hampshire and Sussex, which were described 

 by Dr. L. S. Palmer, bear very directly upon the 

 question of the equation with Continental deposits. 

 Dr. Palmer, who worked in collaboration with a 

 geologist, had endeavoured to relate climate and 

 deposits with implements. As a result, the ioo ft. 

 terraces and beaches show a warm fauna associated 



with Acheulean and early Mousterian implements ; 

 the 50 ft. and 15 ft. terraces a cold fauna associated 

 with Mousterian implements, the cold period being 

 interrupted by a slightly warmer period which 

 justified the division of this phase into two parts. 

 In the superficial brick earths were the Aurignacian, 

 and over the latest Combe rock were the Magdalenian 

 implements. Dr. Palmer found a correspondence 

 between climate, culture, and land oscillations. The 

 investigations were carried out without reference to 

 nomenclature, but on comparison, corresponded with 

 the Continental system of Penck. 



At this point the discussion closed. If it had 

 attained no very definite conclusion, the air had 

 been cleared. One definite question has been formu- 

 lated for further investigation, and it has been shown 

 that a considerable body of opinion is approaching 

 some kind of an agreement as to the manner in which 

 the evidence in Britain may be brought into relation 

 with that of the Continent. 



Generation and Utilisation of Cold. 



'THE general discussion on the generation and 

 -*- utilisation of cold which was held at the 

 Institution of Electrical Engineers on October 16 

 was organised jointly by the Faraday Society and 

 the British Cold Storage and Ice Association. 



Although the papers read at the meeting dealt with 

 various aspects of the liquefaction of gases, there 

 were no contributions from the refrigerating industry. 

 Possibly the applications of cold for the preservation 

 of food stuffs have become so standardised that our 

 refrigerating engineers do not interest themselves in 

 new developments. It was intended that the 

 opening paper of the discussion should be read by 

 Prof. H. Kamerlingh Onnes, but owing to the death 

 of his colleague, Prof. Kuenen, he was unable to be 



NO. 2766, VOL. I IO] 



present. Consequently Dr. C. A. Crommelin com- 

 municated Prof. Onnes's paper as well as his own. 



The Leyden cryogenic laboratory has been engaged 

 on low-temperature investigations for the past 

 thirty-five years, and such magnificent work has 

 been done there that any communi- 

 cation emanating from this special- 

 ised institution is read with con- 

 siderable interest. 



Dr. Crommelin's paper was of 

 the nature of a general description 

 of the methods of experiment 

 whereby they obtained any de- 

 sired temperature below zero centi- 

 grade and maintained this tempera- 

 ture constant within o-oi° C. The 

 equipment of the cryogenic labora- 

 tory is essentially a series of plants 

 working on regenerative Pictet 

 cycles down' to liquid nitrogen 

 temperatures. Below this, liquid 

 hydrogen and liquid helium are 

 employed. In the Pictet cycles 

 methyl chloride, nitrous oxide, 

 ethylene, methane, oxygen, and 

 nitrogen are used. Any one of the 

 substances boiling under appro- 

 priate pressure will give a range 

 ] of steady temperatures. By these 

 means a range from - 24° C. to 

 - 270 C. is obtained which is 

 complete but for short gaps. 



Cryostats containing the differ- 

 ent liquids are thermally insulated 

 by vacuum walled vessels and the 

 losses reduced to a minimum by 

 the immersion of the apparatus in 

 baths of the commoner elements 

 such as liquid oxygen. 



For the range -259°to -269°C, 

 which cannot be obtained by the use of a boiling 

 liquid, a hydrogen vapour cryostat is employed, the 

 vapour being heated electrically to the desired tem- 

 perature and circulated around the experimental 

 bulb. 



The paper also contains some interesting data as 

 to the capacity of the plant, and it is stated that 

 liquid hydrogen can be produced at the rate of more 

 than 13 litres per hour. A high degree of purity is 

 required in the gases employed, and it appears that 



